Process for the manufacture of diphenylamin



A. E. HOULEHAN.

PROCESS FOR THE MANUFACTURE OF DIPHENYLAMIN, APPLICATION FILED MAYZS, 1917.

1,392,942, Patented Oct. 11,1921.

- anveuto't umra STATS FFICE.

ARTHUR EARL HOULEHAN, OF WILMINGTON, DELAWARE, ASSIGNOR TO E. I. no POINT I, ha INEMOUBS AND COMPANY, OF WILMINGTON DELAWARE, A CORPORATION OF DELAWARE. a

Specification of Letters Patent.

Patented Oct 11, 1921,

Application filed May 25, 191?. Serial No. 170,808.

y invention relates to a process of producing diphenylamin from anilin, and comprises heating anilin, preferably in the presence of water, with a halogen-containing substance which is capable of providing a free halogen or the hydrid thereof during the reaction. 7

v The object of my invention is to provide a process-for producing diphenylamin by the treatment of anilin with an iodid.

The object of my invention is to carry out the process of this character in an advantageous manner furthermore, by the use of a particular iodid or certain iodids.

' A further object of my invention is to insure the production of the diphenylamin by controlling the conditions of the process,par

ticularly the presence of water.

While my invention is capable of. being carried out in many different ways, for the purpose of illustration, I shall describe only certain ways of carrying out the same, and while my invention is capable of bein carried out in connection with many iiferent forms of apparatus, I will describe only one form of apparatus to be used in connection with carrying out my invention, in the accompanying drawings, in which+ The figure is a vertical section "of an apparatus which may befused in connection with my invention.

In the drawings I have shown an autoclave 1, comprising a container 2, which may be-made of iron, to which there is adapted to be attached a lid 3, which may also be made of iron and which may be attached to the container 2 by means of bolts 4. On the lid? there is, furthermore, provided a column 5, havin a valved outlet pipe 6, at its let upper end. he autoclave may havean out-- ipe 7 having ahand valve 8 leading to a still 9 of any suitable character, having a vapor outlet pipe 10 leading to a condenser 11.

I may for example carry out my invention as follows:

A quantity of anilin mixed with a small percentage of a catalyst, as, for example, am-' monium iodid, the catalyst, however, preferably being about 1% to4% of the anilin, is inserted in the autoclave 1 and the cover 3 tightly securedv to the same. Heat is now applied to the autoclave and thecontents are subjected to heat and pressure in this manner for any suitable length of time, but preferably 48 hours. The anilin becomes trans formed into diphenylamin, in accordance with the following equation:

outlet pipe 6, I am enabled to release by means of said pipe 6 the ammonia, which accumulates from time to time without losing the anilin, as the column 5 has the effect of condensing the anilin-and returning the same to the container 2 under the cooling effect of the air, while the ammonia accumulates in the top of the column 5. In this way the reaction may be carried more-nearly to completion, owing to the fact that the ammonia produced in the process is removed from the presence-of the anilin.

With the percentages of the iodin catalyst less than 1%, the reaction takes place very slowly, and, therefore, requires heating for a long period of time, thus increasing the cost of operation. With amounts of the catalyst greater than 4% the rate of condensation is increased to some extent, but this is oil-set by the greater loss of material, due to the increased formation of tar.

I have found, furthermore, that the temperature used should be about 300 (3., although temperatures from 275 to 300 C. may be used, as at lower temperatures the rate of formationisvery slow and at higher temperatures the formation of tar is increased.

The catalyst used may be iodin, but preferably instead of iodin I use a compound vide either a free halogen or the hydrid thereof.

I have found, furthermore, that in carrying out the process it is practically essential that a small amount of water be present,

preferably about 1% of water, but the best.

results are obtained by an amount of water of not less than .75% and not more than 2%, as (an amount of water above this percentage is objectionableowing to the increased pressure although it is not disadvantageous chemically. I have found that the condensation from anilin to diphenylamin could not take place in the absence of water. Ordinarily the commercial anilin and iodid contain suflicient Water to enable the process to be carried out without further addition of Water, for although the percentage of water .above mentioned is preferred, yet only a trace of Water is absolutely necessary. After the mixture has been digested in the autoclave 1, it is blown out through the pipe 7 into the still 9, and there distilled, three fractions being collected. The first fraction, which distils up to 200 C. consists mainly of unchanged anilin, together with a small amount of diphenylamin and is stored for re-digestion with a fresh amount of catalyst. The second fraction, distilling between 200 and 3009 C. consists of a mixture of anilin with .a larger amount of diphenylamin. The larger part of the latter may be recovered from this fraction by re-distillation. The main body of the diphenylamin is collected in the fraction which distils over and above 300 C. A tarry residue is left in the still from which the catalyst can be recovered.

While I have described my invention above in detail, I wish it to be understood that many changes may be made therein, without departing from the spirit of my invention.

1. The process of condensing anilin to diphenylamin which comprises heating anilin to a temperature of from about 275 to 300 C. in the presence of water with a small proportion of a halogen-containing substance'as the active catalyst, which sub- 39 naaaeaa stance rovides a source of a free halogen or the h rid thereof in the process.

2. The process of condensing anilin to diphenylamin which comprises heating anilin in the presence of not more than 2% of water with a small proportion of a halogen-containing substance, which substance provides a source of a free halogen orthe hydrid thereof in the process.

3. The process of condensing anilin to diphenylamin which comprises heating anilin in the presence of not more than 2% of water with a small proportion of an iodincontaining substance as the active catalyst.

4.. The process of condensing anilin to diphenylalnin which comprises heating anilin with a small proportion of an iodid in the presence of water.

5. The process of condensing anilin to diphenylamin which comprises heating anilin with a small' proportion of an iodid in the presence of not more than 2% of Water.

6. The process of condensing anilin to diphenylamin which comprises heating anilin with ammonium iodid in the presence of water.

7. The process of condensing anilin to diphenylamin which comprises heating ani lin with ammonium iodid in the presence of not more than 2% of water.

8. The process of condensing anilin to diphe'nylamin which comprises heating anilin with a catalyst capable of causing the formation of ammonia and releasing the am: monia during the process. u

9. The process of condensing anilin to diphenylamin which comprises heating anilin with a catalyst capable of causing the formation of ammonia, and releasing the ammonia during the process without releasin any substantial portion of the unchanged su stances being treated.

10. The process of condensing anilin to diphenylamin which comprises heating anilin to a temperature of from about 275 to 300 C. with a small proportion of an iodid in the presence of not more than 2% of water. I

In testimony that I claim the foregoing I have hereunto set my hand.

ARTHUR EARL HOULEHAN.

Witnesses A. M. GoRMAN, P. E. STRIoKLAND. 

